Should actor massScale affect all aspects of simulation?

[josemendez]

In any case, is that expected result? Should mass scale affect everything in this way? If yes, then what is affected except constraint? (I get completely different lambdas)

Hi,

Mass affects acceleration due to forces, since F=ma and a = F/m.

So anything that involves forces (which is pretty much everything in the simulation - except for gravity which is an acceleration) will be affected by it. This includes aerodynamics (drag and lift forces), maybe this is what you mean by “velocity applied to body”?

It also affects the rigidness of rods, since it scales rotational mass which is the scale of the inertia tensor. As a result, rods with smaller rotational mass are more easily bent by external forces, regardless of compliance.

Lambdas reported by constraints will also of course be different as a result, since they're a measure of the force applied by the constraint: if you have two 5kg objects and must move them closer to each other to meet a distance constraint, the force you should apply to move them is larger than it would need to be if they weighed 1 kg.

It seems it influences collision with static colliders too and also velocity applied to body, but shouldn't velocity be mass indepentent? (I add velocity with spring to controll rod movement)

Velocity (as a result of forces) is not independent of mass at all: if it were, a given force would always result in the same velocity regardless of the mass of the object it is applied to. This would make mass meaningless.

A spring (F=-kx) is a force so the resulting change in velocity (acceleration) must be affected by mass.

Kind regards